Mythbusters to take on "the plane and the treadmill" conundrum?

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smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: Garth
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: Fraggable
Look man according to the wording of the question, the wheels would end up spinning infinitely fast before the plane left the ground.
This is a misunderstanding of the wording of the problem. As given, the treadmill matches the ground speed of the plane, not the rotational speed of the wheels. The latter isn't a coherent idea since the reverse movement of the treadmill directly affects the rotational speed of the wheels.

The later isn't incoherent.
Yes it is. If the wheels roll +1 ft, then the tread mill will move -1 ft. Yet, because of the contact of the wheel with the treadmill, the wheel would have to move a net 2 ft as the reverse motion of the treadmill moves the wheel. Contradiction.

And is in fact how most people think about treadmill. A device that will keep the object on top of it is the same position. Most treadmill are really short because people stay in the same location.
That's not how I think of a treadmill. Maybe that's why I don't have the apparent mental block that yourself and MasonLuke do.

When I went to the gym to today everyone on the treadmill had a ground speed of zero. Maybe you have odd gyms where every your from.
Anyways back to your stupidity:
The plane can't go +1 feet without violating the condition of the treadmill matching the speed of the plane. The plane is going 45 mph relative to the treadmill then the treadmill is going backwards are 45 mph. Net result is no motion.

 

Cerpin Taxt

Lifer
Feb 23, 2005
11,940
542
126
Originally posted by: MasonLuke
This is the actual question, i did not write this:


?Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway. The conveyer belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?"



Designed to EXACTLY match the speed of the wheels = no friction.

Kids, be proud of yourselves, you and all the ATOT crew PROVED the plane wont fly.


/thread
As I explained, that formulation of the problem is incoherent. The only reasonable interpretation is that the conveyor matches the speed of the plane. Or, if you want to be pedantic (and it seems you do), it doesn't stipulate the rotational speed of the wheels. The "speed of the wheels" must therefore obviously denote the speed of the axles relative to the ground, which is no different than the ground speed of the plane.

That doesn't also change the fact that the majority of the various formulations of the problem stipulate the coherent scenario of the conveyor matching the plane speed.

You still fail.

 

Cerpin Taxt

Lifer
Feb 23, 2005
11,940
542
126
Originally posted by: smack Down

When I went to the gym to today everyone on the treadmill had a ground speed of zero.
How many of them were propelling themselves with jet engines?

Maybe you have odd gyms where every your from.
Maybe my mind features cognitive capabilities that yours lacks, disabling you from assembling a properly relevant analogy.

Anyways back to your stupidity:
The plane can't go +1 feet without violating the condition of the treadmill matching the speed of the plane. The plane is going 45 mph relative to the treadmill then the treadmill is going backwards are 45 mph. Net result is no motion.
No, the net result is the wheels spinning at 90mph.

EDIT: I notice you assume that the plane is going "45 mph relative to the treadmill" -- that isn't stipulated in the problem either. Plane speed is almost universally measured in airspeed, which in this case, since we are to assume no wind, is identical to ground speed.

 

mugs

Lifer
Apr 29, 2003
48,920
46
91
Originally posted by: Garth
Originally posted by: MasonLuke
This is the actual question, i did not write this:


?Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway. The conveyer belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?"



Designed to EXACTLY match the speed of the wheels = no friction.

Kids, be proud of yourselves, you and all the ATOT crew PROVED the plane wont fly.


/thread
As I explained, that formulation of the problem is incoherent. The only reasonable interpretation is that the conveyor matches the speed of the plane. Or, if you want to be pedantic (and it seems you do), it doesn't stipulate the rotational speed of the wheels. The "speed of the wheels" must therefore obviously denote the speed of the axles relative to the ground, which is no different than the ground speed of the plane.

That doesn't also change the fact that the majority of the various formulations of the problem stipulate the coherent scenario of the conveyor matching the plane speed.

You still fail.

:thumbsup:

MasonLuke, you ought to quit being so condescending when you clearly have no clue what you're talking about.

I'm curious about how old you are. I'm going to guess between 18 and 21?

Edit:
Also, the question you posted asks "Can the plane take off?" Not "Will the plane take off." Even if you assume for whatever reason that the plane cannot summon the power to move itself along the treadmill, the plane CAN take off. As many people have correctly pointed out, it is air moving across the wings that generates lift. You don't need to move relative to the ground in order to get air to move across the wings. Big gust of wind. You lose. Thanks for playing, "kid" :roll:
 

smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: Garth
Originally posted by: smack Down

When I went to the gym to today everyone on the treadmill had a ground speed of zero.
How many of them were propelling themselves with jet engines?

Maybe you have odd gyms where every your from.
Maybe my mind features cognitive capabilities that yours lacks, disabling you from assembling a properly relevant analogy.

Anyways back to your stupidity:
The plane can't go +1 feet without violating the condition of the treadmill matching the speed of the plane. The plane is going 45 mph relative to the treadmill then the treadmill is going backwards are 45 mph. Net result is no motion.
No, the net result is the wheels going 90mph.

It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.

45 + -45 = 0 for all of them.
 

Cerpin Taxt

Lifer
Feb 23, 2005
11,940
542
126
Originally posted by: smack Down
It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.
The difference is essential. Reverse motion would negate the forward propulsion of a vehicle that propelled itself by pushing on the ground.

Airplanes do not. Airplanes propel themselves by pushing on the air.

45 + -45 = 0 for all of them.
I almost feel sorry for you. Almost.

 

mugs

Lifer
Apr 29, 2003
48,920
46
91
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: smack Down

When I went to the gym to today everyone on the treadmill had a ground speed of zero.
How many of them were propelling themselves with jet engines?

Maybe you have odd gyms where every your from.
Maybe my mind features cognitive capabilities that yours lacks, disabling you from assembling a properly relevant analogy.

Anyways back to your stupidity:
The plane can't go +1 feet without violating the condition of the treadmill matching the speed of the plane. The plane is going 45 mph relative to the treadmill then the treadmill is going backwards are 45 mph. Net result is no motion.
No, the net result is the wheels going 90mph.

It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.

45 + -45 = 0 for all of them.

You want to talk about cars? Let's talk about cars. A car has two pairs of wheels. Usually two of these are driving wheels, and two of these are freely rotating wheels. You can think of the driving wheels as analogous to the plane's jet engines, and the freely rotating wheels as analogous to the plane's wheels.

Put the car on a treadmill with just the non-driving wheels on the treadmill and the driving wheels off the treadmill. The treadmill does not act on the driving wheels, just like it does not act on the jet engines of the plane. The treadmill matches the speed of the car in the opposite direction.

You can still drive the car, right? The freely rotating wheels on the treadmill don't slow you down. You get the car up to 5 mph with the wheels that are on solid ground, and the freely rotating wheels rotate at 10 mph because of the treadmill.

Same situation! The treadmill can't slow the plane down, because the wheels are freely rotating.
 

smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: Garth
Originally posted by: smack Down
It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.
The difference is essential. Reverse motion would negate the forward propulsion of a vehicle that propelled itself by pushing on the ground.

Airplanes do not. Airplanes propel themselves by pushing on the air.

45 + -45 = 0 for all of them.
I almost feel sorry for you. Almost.

Well when you at least learn to add negative numbers come back to this thread.
 

smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: mugs
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: smack Down

When I went to the gym to today everyone on the treadmill had a ground speed of zero.
How many of them were propelling themselves with jet engines?

Maybe you have odd gyms where every your from.
Maybe my mind features cognitive capabilities that yours lacks, disabling you from assembling a properly relevant analogy.

Anyways back to your stupidity:
The plane can't go +1 feet without violating the condition of the treadmill matching the speed of the plane. The plane is going 45 mph relative to the treadmill then the treadmill is going backwards are 45 mph. Net result is no motion.
No, the net result is the wheels going 90mph.

It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.

45 + -45 = 0 for all of them.

You want to talk about cars? Let's talk about cars. A car has two pairs of wheels. Usually two of these are driving wheels, and two of these are freely rotating wheels. You can think of the driving wheels as analogous to the plane's jet engines, and the freely rotating wheels as analogous to the plane's wheels.

Put the car on a treadmill with just the non-driving wheels on the treadmill and the driving wheels off the treadmill. The treadmill does not act on the driving wheels, just like it does not act on the jet engines of the plane. The treadmill matches the speed of the car in the opposite direction.

You can still drive the car, right? The freely rotating wheels on the treadmill don't slow you down. You get the car up to 5 mph with the wheels that are on solid ground, and the freely rotating wheels rotate at 10 mph because of the treadmill.

Same situation! The treadmill can't slow the plane down, because the wheels are freely rotating.

Free rolling does not mean no effect. A wheel can never be 100% decoupled from the system. Unless of course it is mass less.
 

MasonLuke

Senior member
Aug 14, 2006
413
0
0

[/quote]

okay, now you're missing a point. if they're gonna test this, then real world does apply. obviously, and thank you for taking time out of your genius day to point this ouit, there won't be too many planes found on too many treadmills in the near future.

i take that back...this point isn't too clear for me. could you explain to me why i will "NEVER see a plane on a treadmill that can counter the planes wheels percisely in the real world, let alone a plane on a treadmill"...[/quote]


the airplane needs to lose some weight so the engineers put the airplane on the treadmill a couple hours a week. dumb dumber you the dumbest. sorry if the truth hurts.

 

Cerpin Taxt

Lifer
Feb 23, 2005
11,940
542
126
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: smack Down
It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.
The difference is essential. Reverse motion would negate the forward propulsion of a vehicle that propelled itself by pushing on the ground.

Airplanes do not. Airplanes propel themselves by pushing on the air.

45 + -45 = 0 for all of them.
I almost feel sorry for you. Almost.

Well when you at least learn to add negative numbers come back to this thread.
I take it back, I don't even "almost" feel sorry for you.

Perhaps you can explain to us exactly HOW that -45 affects the forward propulsion of the plane rather than being completely translated into rotational speed of the wheels.

Here's a little exercise in self-discovery for you.

Go buy yourself one of the "Hot Wheels" style toy cars. Just a small little matchbox racer. Any one will do.

Then, take it to your gym, and start the treadmill at a speed of, say 10mph. As it moves, set the toy car on the rear of the treadmill and roll it forward to the front. Try different settings on the treadmill and different rates of pushing the car.

Let us know how that -10mph affects the rates at which you are able to push the toy car from the rear to the front of the treadmill. I'll particularly interested in your report of what treadmill speed prevents you from pushing the car forward at all.
 

MasonLuke

Senior member
Aug 14, 2006
413
0
0
Originally posted by: mugs
Originally posted by: Garth
Originally posted by: MasonLuke
This is the actual question, i did not write this:


?Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway. The conveyer belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?"



Designed to EXACTLY match the speed of the wheels = no friction.

Kids, be proud of yourselves, you and all the ATOT crew PROVED the plane wont fly.


/thread
As I explained, that formulation of the problem is incoherent. The only reasonable interpretation is that the conveyor matches the speed of the plane. Or, if you want to be pedantic (and it seems you do), it doesn't stipulate the rotational speed of the wheels. The "speed of the wheels" must therefore obviously denote the speed of the axles relative to the ground, which is no different than the ground speed of the plane.

That doesn't also change the fact that the majority of the various formulations of the problem stipulate the coherent scenario of the conveyor matching the plane speed.

You still fail.

:thumbsup:

MasonLuke, you ought to quit being so condescending when you clearly have no clue what you're talking about.

I'm curious about how old you are. I'm going to guess between 18 and 21?

Edit:
Also, the question you posted asks "Can the plane take off?" Not "Will the plane take off." Even if you assume for whatever reason that the plane cannot summon the power to move itself along the treadmill, the plane CAN take off. As many people have correctly pointed out, it is air moving across the wings that generates lift. You don't need to move relative to the ground in order to get air to move across the wings. Big gust of wind. You lose. Thanks for playing, "kid" :roll:

you are stupid. listen to what you are saying. you are saying that if you fart on the wings, the plane will fly? you know how heavy a plane is? you will need hurricane force winds, but again, u just added something to suit your needs.

all you have is a plane and a treadmill. no fart, no rope, no wind, ect.
 

Cerpin Taxt

Lifer
Feb 23, 2005
11,940
542
126
Originally posted by: Garth
Originally posted by: MasonLuke
This is the actual question, i did not write this:


?Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway. The conveyer belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?"



Designed to EXACTLY match the speed of the wheels = no friction.

Kids, be proud of yourselves, you and all the ATOT crew PROVED the plane wont fly.


/thread
As I explained, that formulation of the problem is incoherent. The only reasonable interpretation is that the conveyor matches the speed of the plane. Or, if you want to be pedantic (and it seems you do), it doesn't stipulate the rotational speed of the wheels. The "speed of the wheels" must therefore obviously denote the speed of the axles relative to the ground, which is no different than the ground speed of the plane.

That doesn't also change the fact that the majority of the various formulations of the problem stipulate the coherent scenario of the conveyor matching the plane speed.

You still fail.

No comment?
 

smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: Garth
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: smack Down
It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.
The difference is essential. Reverse motion would negate the forward propulsion of a vehicle that propelled itself by pushing on the ground.

Airplanes do not. Airplanes propel themselves by pushing on the air.

45 + -45 = 0 for all of them.
I almost feel sorry for you. Almost.

Well when you at least learn to add negative numbers come back to this thread.
I take it back, I don't even "almost" feel sorry for you.

Perhaps you can explain to us exactly HOW that -45 affects the forward propulsion of the plane rather than being completely translated into rotational speed of the wheels.

Here's a little exercise in self-discovery for you.

Go buy yourself one of the "Hot Wheels" style toy cars. Just a small little matchbox racer. Any one will do.

Then, take it to your gym, and start the treadmill at a speed of, say 10mph. As it moves, set the toy car on the rear of the treadmill and roll it forward to the front. Try different settings on the treadmill and different rates of pushing the car.

Let us know how that -10mph affects the rates at which you are able to push the toy car from the rear to the front of the treadmill.

So you agree that 45 + -45 = 0. I want to make sure you understand that before I go any further into debate with you. Because before you claimed that as equal 90. I don't want to bother with someone who doesn't understand addition no less physics.

As to how the treadmill effects the speed of the plane. Short answer not my problem, if that is what the question says the means are not an issue. Long answer go put that toy car on the treadmill. Lets start at 1 mph does it stay in one spot or does it get thrown off the back? Now increase the speed to 10 mph does it stay in one spot or get thrown off the back?

Did the car get thrown off the back faster at 1 mph then at 10 mph?
 

Cerpin Taxt

Lifer
Feb 23, 2005
11,940
542
126
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: smack Down
It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.
The difference is essential. Reverse motion would negate the forward propulsion of a vehicle that propelled itself by pushing on the ground.

Airplanes do not. Airplanes propel themselves by pushing on the air.

45 + -45 = 0 for all of them.
I almost feel sorry for you. Almost.

Well when you at least learn to add negative numbers come back to this thread.
I take it back, I don't even "almost" feel sorry for you.

Perhaps you can explain to us exactly HOW that -45 affects the forward propulsion of the plane rather than being completely translated into rotational speed of the wheels.

Here's a little exercise in self-discovery for you.

Go buy yourself one of the "Hot Wheels" style toy cars. Just a small little matchbox racer. Any one will do.

Then, take it to your gym, and start the treadmill at a speed of, say 10mph. As it moves, set the toy car on the rear of the treadmill and roll it forward to the front. Try different settings on the treadmill and different rates of pushing the car.

Let us know how that -10mph affects the rates at which you are able to push the toy car from the rear to the front of the treadmill.

So you agree that 45 + -45 = 0. I want to make sure you understand that before I go any further into debate with you.
Of course I do. I just realize what you don't: that this equation doesn't model the scenario.

Because before you claimed that as equal 90.
No, I didn't. You're simply too dense to realize what I was saying.

I don't want to bother with someone who doesn't understand addition no less physics.
If only I had your restraint I wouldn't be talking to you.

As to how the treadmill effects the speed of the plane. Short answer not my problem, if that is what the question says the means are not an issue.
The question doesn't say that, though. You appear to struggle with many types of comprehension.

Long answer go put that toy car on the treadmill. Lets start at 1 mph does it stay in one spot or does it get thrown off the back? Now increase the speed to 10 mph does it stay in one spot or get thrown off the back?

Did the car get thrown off the back faster at 1 mph then at 10 mph?
Not if I push it, analogously to equipping the car with a jet engine.

To build upon that scenario, imagine that you held the car stationary with the wheels in contact with the treadmill. The treadmill can and will move underneath it and spin the car's wheels, obviously. The car moves at 0 mph (because you are holding it still against the treadmill), the treadmill moves at -10 mph, and the rotational speed of the wheels is 10 mph.

Now, you can push the car forward at a rate of 10mph (airspeed/groundspeed) along the treadmill which is, again, moving at -10 mph. Thus, the car is covering a greater distance with respect to the treadmill surface than it is relative to the ground. The wheels must spin at the 10 mph forced by the treadmill motion PLUS the 10 mph forced by the pushing movement of the car. The result is the wheels spinning at a rate equal to that which they would if the car were moving along a stationary surface at 20 mph.

This is really very simple. In all seriousness, you should probably have yourself evaluated because you may have a very real learning disability.
 

jimbob200521

Diamond Member
Apr 15, 2005
4,108
29
91
Originally posted by: MasonLuke

okay, now you're missing a point. if they're gonna test this, then real world does apply. obviously, and thank you for taking time out of your genius day to point this ouit, there won't be too many planes found on too many treadmills in the near future.

i take that back...this point isn't too clear for me. could you explain to me why i will "NEVER see a plane on a treadmill that can counter the planes wheels percisely in the real world, let alone a plane on a treadmill"...[/quote]


the airplane needs to lose some weight so the engineers put the airplane on the treadmill a couple hours a week. dumb dumber you the dumbest. sorry if the truth hurts.

[/quote]

MasonLuke: the perfect example for why dropping out of High School, or in his case, grade school, is bad. This person...err...troll...needs to stop being fed. He is either mentally unable to comprehend this problem, or is a very good troll. Either way, this is a lose-lose situation. We are not going to convince him no matter what we say. Heck, if this myth was done by Mythbusters, I wouldn't be surprised if MasonLuke keeps arguing that it would not take off.

Also, MasonLuke: Do you think that calling other people stupid and talking down to them is a good way to go about debating a point? It really does nothing for helping you and your case...
 

randay

Lifer
May 30, 2006
11,018
216
106
I just put a hot wheel on a treadmill and turned the treadmill on to the maximum setting. What I observed was the hot wheels accelerating forward at infinite speed and then flying off the treadmill and disappearing into the wall. I could not find the hot wheels after this experiment. If you try this at home I advise to make sure nothing is in front of the treadmill.
 

smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: Garth
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: smack Down
Originally posted by: Garth
Originally posted by: smack Down
It doesn't matter what we are talking about. There is no difference for this part of the discussion between a jet, a car, or a person.
The difference is essential. Reverse motion would negate the forward propulsion of a vehicle that propelled itself by pushing on the ground.

Airplanes do not. Airplanes propel themselves by pushing on the air.

45 + -45 = 0 for all of them.
I almost feel sorry for you. Almost.

Well when you at least learn to add negative numbers come back to this thread.
I take it back, I don't even "almost" feel sorry for you.

Perhaps you can explain to us exactly HOW that -45 affects the forward propulsion of the plane rather than being completely translated into rotational speed of the wheels.

Here's a little exercise in self-discovery for you.

Go buy yourself one of the "Hot Wheels" style toy cars. Just a small little matchbox racer. Any one will do.

Then, take it to your gym, and start the treadmill at a speed of, say 10mph. As it moves, set the toy car on the rear of the treadmill and roll it forward to the front. Try different settings on the treadmill and different rates of pushing the car.

Let us know how that -10mph affects the rates at which you are able to push the toy car from the rear to the front of the treadmill.

So you agree that 45 + -45 = 0. I want to make sure you understand that before I go any further into debate with you.
Of course I do. I just realize what you don't: that this equation doesn't model the scenario.

Because before you claimed that as equal 90.
No, I didn't. You're simply too dense to realize what I was saying.

I don't want to bother with someone who doesn't understand addition no less physics.
If only I had your restraint I wouldn't be talking to you.

As to how the treadmill effects the speed of the plane. Short answer not my problem, if that is what the question says the means are not an issue.
The question doesn't say that, though. You appear to struggle with many types of comprehension.

Long answer go put that toy car on the treadmill. Lets start at 1 mph does it stay in one spot or does it get thrown off the back? Now increase the speed to 10 mph does it stay in one spot or get thrown off the back?

Did the car get thrown off the back faster at 1 mph then at 10 mph?
Not if I push it, analogously to equipping the car with a jet engine.

To build upon that scenario, imagine that you held the car stationary with the wheels in contact with the treadmill. The treadmill can and will move underneath it and spin the car's wheels, obviously. The car moves at 0 mph (because you are holding it still against the treadmill), the treadmill moves at -10 mph, and the rotational speed of the wheels is 10 mph.

Now, you can push the car forward at a rate of 10mph (airspeed/groundspeed) along the treadmill which is, again, moving at -10 mph. Thus, the car is covering a greater distance with respect to the treadmill surface than it is relative to the ground. The wheels must spin at the 10 mph forced by the treadmill motion PLUS the 10 mph forced by the pushing movement of the car. The result is the wheels spinning at a rate equal to that which they would if the car were moving along a stationary surface at 20 mph.

This is really very simple. In all seriousness, you should probably have yourself evaluated because you may have a very real learning disability.

Would you like a cookie for being able to move a car on a treadmill. That really isn't something that is hard.

Now try moving said car on a treadmill that will increase its speed to prevent forward motion?
 

smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Anyone wishing to show the plane can take off or the question is invalid under the assumption that the treadmill matches the speed of the plane relative to the treadmill please just leave out any crappy analogies and write the equations for the interaction between the wheels, treadmill and plane. Then show that the force on the plane via the wheels is bounded anything else is just shows you have no idea what you are talking about.
 

Cerpin Taxt

Lifer
Feb 23, 2005
11,940
542
126
Originally posted by: smack Down

Would you like a cookie for being able to move a car on a treadmill.
No, I would like you to acknowledge that this is precisely analogous to the jet engines pushing the plane.

That really isn't something that is hard.
It seems to be for you.

Now try moving said car on a treadmill that will increase its speed to prevent forward motion?
I quote myself from earlier in th thread, thusly, and like so...

I think it is clear that MasonLuke has misunderstood the stipulations of the problem. He seems to begin with the assumption that the treadmill will move in the opposite direction with whatever speed is necessary to make the plane stand still.

This is not the case, however. The treadmill moves at the same speed as the plane but in the reverse direction. Consequently, the wheels will need to rotate twice as fast to cover the distance the plane would ordinarily travel plus the "pseudo-distance" added by the reverse motion of the treadmmill, which will be precisely equal to the distance that the plane would cover in the first place.

In order for the treadmill to force the plane to remain motionless, it would have to move at speeds MUCH greater than the forward speed of the plane. For that matter, if the plane was motionless, how could one conclude that the treadmill was moving at all? The precondition is that the treadmill moves as fast as the plane. If you assume the belt moves, you've already conceded that the plane moves. If you're arguing that the plane stands still, then it can't be due to the movement of the belt. When the plane's speed is zero, so should be the belt's.
 

jimbob200521

Diamond Member
Apr 15, 2005
4,108
29
91
Originally posted by: smack Down
Anyone wishing to show the plane can take off or the question is invalid under the assumption that the treadmill matches the speed of the plane relative to the treadmill please just leave out any crappy analogies and write the equations for the interaction between the wheels, treadmill and plane. Then show that the force on the plane via the wheels is bounded anything else is just shows you have no idea what you are talking about.

So you believe the plane will not take off?

Ok, if so, tell me this; how does the treadmill counter the thrust that the jets/propeller provide?
 

smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: Garth
Originally posted by: smack Down

Would you like a cookie for being able to move a car on a treadmill.
No, I would like you to acknowledge that this is precisely analogous to the jet engines pushing the plane.

That really isn't something that is hard.
It seems to be for you.

Now try moving said car on a treadmill that will increase its speed to prevent forward motion?
I quote myself from earlier in th thread, thusly, and like so...

I think it is clear that MasonLuke has misunderstood the stipulations of the problem. He seems to begin with the assumption that the treadmill will move in the opposite direction with whatever speed is necessary to make the plane stand still.

This is not the case, however. The treadmill moves at the same speed as the plane but in the reverse direction. Consequently, the wheels will need to rotate twice as fast to cover the distance the plane would ordinarily travel plus the "pseudo-distance" added by the reverse motion of the treadmmill, which will be precisely equal to the distance that the plane would cover in the first place.

In order for the treadmill to force the plane to remain motionless, it would have to move at speeds MUCH greater than the forward speed of the plane. For that matter, if the plane was motionless, how could one conclude that the treadmill was moving at all? The precondition is that the treadmill moves as fast as the plane. If you assume the belt moves, you've already conceded that the plane moves. If you're arguing that the plane stands still, then it can't be due to the movement of the belt. When the plane's speed is zero, so should be the belt's.

If you wish to come into a thread with 800 post at least read a few of them and you will see that this has already been gone over may times.

Besides you where trying to prove that the other reading was invalid. Can you at least add and remember what you are arguing or is that to much to ask?
 

MasonLuke

Senior member
Aug 14, 2006
413
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Originally posted by: jimbob200521
Originally posted by: smack Down
Anyone wishing to show the plane can take off or the question is invalid under the assumption that the treadmill matches the speed of the plane relative to the treadmill please just leave out any crappy analogies and write the equations for the interaction between the wheels, treadmill and plane. Then show that the force on the plane via the wheels is bounded anything else is just shows you have no idea what you are talking about.

So you believe the plane will not take off?

Ok, if so, tell me this; how does the treadmill counter the thrust that the jets/propeller provide?

Garth, the thurst on the jets moves the plane via the wheels, nothing else. if the treadmill counters the movement of the wheels, the plane is standing still. therefore, no forward movement, no lift, unless Mugs farts on the wings. LOL.

 

smack Down

Diamond Member
Sep 10, 2005
4,507
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Originally posted by: jimbob200521
Originally posted by: smack Down
Anyone wishing to show the plane can take off or the question is invalid under the assumption that the treadmill matches the speed of the plane relative to the treadmill please just leave out any crappy analogies and write the equations for the interaction between the wheels, treadmill and plane. Then show that the force on the plane via the wheels is bounded anything else is just shows you have no idea what you are talking about.

So you believe the plane will not take off?

Ok, if so, tell me this; how does the treadmill counter the thrust that the jets/propeller provide?

My theory is simple if the plane moving forward cause the wheels to roll. Rolling the wheels backwards cause the plane to go backwards. All the thrust goes towards accelerating the wheels on the treadmill.